The compound 1,4-dicyclopropyl-1,3-butadiyne is known in the literature and has been synthesized by oxidative coupling reaction using excessive reagent [CuCl/Cu(OAc)2/Pyridine/MeOH] in moderate yield (56–70%). The reported methods require pyridine as a solvent. The removal and recovery of pyridine are problematic in an industrial scale synthesis and moreover, the reaction requires a long period (e.g., 3 days) of time
The synthesis of 1,4-dicyclopropyl-1,3-butadiyne was improved by oxidative coupling reaction of trimethylsilyl cyclopropyl acetylene using CuCl (12 eq.)/Cu(OAc)2 (16 eq.) in MeOH/Pyridine [Angew. Chem. Int. Ed. Engl. 1995, ˜, 781]. This modification furnished 1,4-dicyclopropyl-1,3-butadiyne in 70% yield in 12 hours.
In addition to the lengthy reaction time and moderate yields, the above processes require the use of pyridine, the recovery and removal of which is problematic.
Accordingly, there is need and market for a process that overcomes the above prior art shortcomings.
There has now been discovered a method for producing the above butadiynes that is of shorter duration, eliminates the use of pyridine and produces the above compound in increased yields over the prior art.